Synthesis of Ethyl Phenol over Modified HZSM-5 Catalyst in a Fixed Bed Reactor

Abstract

Abstract The selective synthesis of p-ethyl phenol in vapor phase alkylation of phenol with ethanol was investigated in a fixed bed flow reactor on cerium modified zeolite CeZSM5 at temperature 693 K. A series of cerium modified zeolite such as Ce4ZSM54, Ce6ZSM56, Ce8ZSM58, Ce10ZSM5 were prepared by modifying with 4 %, 6 %, 8 % and 10 % ceric ammonium nitrate solution respectively. HZSM-5 zeolite exchanged with 10 % cerium nitrate solution was proved to be the best of all the catalyst used. The modified catalyst was further characterized by SEM, XRD and EDS. Phenol reacted with ethanol to form ethylphenyl ether by O-alkylation, and p-ethylphenol- and o-ethylphenol isomers by C-alkylation; secondary products were m-ethylphenol and dialkylated compounds. Reactions were carried out in the temperature 623 K–693 K, reactant mole ratio 0.2–0.5 over modified HZSM-5 zeolite. The optimum operating condition for maximum selectivity of p-ethyl phenol were EtOH to phenol mole ratio, 4:1; temperature, 623 K; space-time, 10.2 kg h/kmol and 1 atm pressure. A detailed kinetic study was carried out for the ethyl phenol synthesis reaction. From the product distribution pattern, a kinetic model for the reactions was proposed following the Langmuir–Hinshelwood approach. The kinetic and adsorption parameters of the rate equation were determined by non-linear regression analysis. From the kinetic analysis of the experimental data, the apparent activation energy for the reaction was determined as 43.27 kJ/mol.